Add fetch tool for web content retrieval (#65)

Implement a fetch tool that retrieves content from HTTP(S) URLs. Supports
HTML pages (converted to Markdown) and JSON APIs (pretty-printed). Includes
custom headers, configurable timeouts, and content truncation for large
responses.

Co-authored-by: construct-agent <noreply@construct.sh>

Restrict model provider creation to Anthropic for release

Disable all model providers except Anthropic in the CreateModelProvider
handler to ensure only Anthropic is available.

Co-authored-by: construct-agent <noreply@construct.sh>

Alternative setup instructions

Fix message feed scrolling behavior

Configure macOS code signing and notarization (#61)

Add support for signing and notarizing the CLI binary for macOS distribution:
- Create entitlements.xml with necessary permissions for network, file access, and process execution
- Configure code signing in GoReleaser using Developer ID certificate
- Add notarization configuration to submit binaries to Apple's notarization service
- Update release workflow to pass signing and notarization credentials
- Set 20-minute timeout to allow Apple's scanning process to complete

This enables users to run the construct CLI on macOS without warnings.

Co-authored-by: construct-agent <noreply@construct.sh>

Add architecture documentation

• Detail provider abstraction layer supporting Anthropic, OpenAI, Google, xAI, and AWS Bedrock
• Explain data models: Providers, Conversations, Messages, Tasks, Blocks
• Document Task Reconciler reconciliation loop orchestrating user input, model invocations, and tool execution
• Describe CodeAct JavaScript-based tool calling system with Sobek VM sandboxing
• Cover multi-agent architecture with cost optimization and specialization benefits

Co-authored-by: construct-agent <noreply@construct.sh>

Clarify edit agent prompt to reject trivial comments

Reinforce the existing no-trivial-comments rule and provides concrete
guidance to prevent the agent from adding unhelpful inline documentation.

Also update Code Quality Standards to emphasize self-documenting code through
clear naming and structure as a preferred alternative to comments.

Co-authored-by: construct-agent <noreply@construct.sh>

Refactor builtin agent initialization and naming

Key changes:
• Update createBuiltinAgents() to accept ModelProvider pointer instead of ProviderKind
• Query models by provider ID directly rather than using DefaultModel() helper
• Rename builtin agents for clarity: coder → edit, architect → plan
• Introduce fastedit agent (lightweight version using budget model)
• Remove DefaultModel() and BudgetModel() helper methods from AnthropicProvider
• Use module-level constants (AnthropicDefaultModel, AnthropicBudgetModel) directly

Frontend updates:
• Fix key event handler to properly spread command arrays
• Add switchAgentCmd message type to handle agent switching in terminal UI
• Implement executeSwitchAgent() to update task agent via API when switching

Co-authored-by: construct-agent <noreply@construct.sh>

Fix interrupt handling for suspended tasks

Previously, task suspension did not properly cancel running task execution,
causing tasks to continue processing even after being marked as suspended.

Key changes:
• Add TaskSuspendedEvent to distinguish suspension from normal task events
• Subscribe to suspension events in TaskReconciler to cancel active tasks
• Resume tasks when new messages arrive by resetting DesiredPhase to running
• Check DesiredPhase instead of Phase when computing task status

This ensures tasks can be properly interrupted and later resumed without
leaving zombie executions running in the background.

Co-authored-by: construct-agent <noreply@construct.sh>

Disable CGO